PathTracingSpatialTemporalDenoising.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "PathTracingDenoiser.h"
#include "RHIDefinitions.h"
 
#if RHI_RAYTRACING
 
#include "RenderGraphFwd.h"
#include "ScreenPass.h"
 
class FRDGBuilder;
class FScene;
class FViewInfo;
class FRDGTexture;
 
struct FPathTracingSpatialTemporalDenoisingContext
{
    FRDGTexture*    RadianceTexture = nullptr;
    FRDGTexture*    AlbedoTexture = nullptr;
    FRDGTexture*    NormalTexture = nullptr;
    FRDGTexture*    DepthTexture = nullptr;
    FRDGBuffer*     VarianceBuffer = nullptr;
 
    FRDGTexture*    LastDenoisedRadianceTexture = nullptr;
    FRDGTexture*    LastRadianceTexture = nullptr;
    FRDGTexture*    LastAlbedoTexture = nullptr;
    FRDGTexture*    LastNormalTexture = nullptr;
    FRDGTexture*    LastDepthTexture = nullptr;
    FRDGBuffer*     LastVarianceBuffer = nullptr;
 
    // Custom path tracing spacial temporal denoiser result, used by plugins
    TRefCountPtr<UE::Renderer::Private::IPathTracingSpatialTemporalDenoiser::IHistory> SpatialTemporalDenoiserHistory;
 
    int FrameIndex;
 
    static constexpr uint32 kNumberOfPixelShifts = 25;
    static constexpr uint32 kNumberOfShiftsPerTexture = 4;
    static constexpr uint32 kNumberOfPasses = 1;
    static constexpr uint32 kNumberOfTexturesPerPass =
        (kNumberOfPixelShifts + (kNumberOfShiftsPerTexture * kNumberOfPasses) - 1)
        / (kNumberOfShiftsPerTexture * kNumberOfPasses);
 
    // Debug information
    FRDGTexture*    MotionVector = nullptr;
    FRDGTexture*    WarpedSource = nullptr;
 
    // Utility texture
    FRDGTexture* VarianceTexture = nullptr;
};
 
 
int GetPathTracingDenoiserMode(const FViewInfo& View);
bool IsPathTracingDenoiserEnabled(const FViewInfo& View);
bool ShouldEnablePathTracingDenoiserRealtimeDebug();
ETextureCreateFlags GetExtraTextureCreateFlagsForDenoiser();
 
// Calculate the variance per-pixel.
void PathTracingSpatialTemporalDenoisingPrePass(
    FRDGBuilder& GraphBuilder,
    const FViewInfo& View,
    int IterationNumber,
    int MaxSPP,
    FPathTracingSpatialTemporalDenoisingContext& SpatialTemporalDenoisingContext
);
 
void PathTracingSpatialTemporalDenoising(FRDGBuilder& GraphBuilder,
    const FViewInfo& View,
    int DenoiserMode,
    FRDGTexture*& SpatialTemporalDenoisedTexture,
    FPathTracingSpatialTemporalDenoisingContext& SpatialTemporalDenoisingContext);
 
struct FVisualizePathTracingDenoisingInputs
{
    // [Optional] Render to the specified output. If invalid, a new texture is created and returned.
    FScreenPassRenderTarget OverrideOutput;
    FRDGTextureRef SceneColor;
    FRDGTextureRef DenoisedTexture;
    FScreenPassTextureViewport Viewport;
 
    FPathTracingSpatialTemporalDenoisingContext DenoisingContext;
 
    TRDGUniformBufferRef<FSceneTextureUniformParameters> SceneTexturesUniformBuffer;
};
 
FScreenPassTexture AddVisualizePathTracingDenoisingPass(FRDGBuilder& GraphBuilder, const FViewInfo& View, const FVisualizePathTracingDenoisingInputs& Inputs);
 
#endif